Method of washing cooked straw



July 31, 1928.

DE WITT C. AMERINE METHOD OF WASHING COOKED STRAW Filed June 9, 1926 gwuentoz @5% www pressures,

Patented July 31, 1928.

UNITED STATES DE 'W'I'I'IV G. AMERINE, 0F VINCENNES, INDIANA.

METHOD 0F WASHING COOKED STRAW.

Application led June 9, 1926. Serial No. 114,700.

ln the method heretofore employed, straw of all kinds has been placed in a globe rotary boiler and cooked under various steam the straw being saturated with a solution of lime water which has a tendency during the cooking period of softening the straw to a point where the ibers could be separated in the next operation in manufacturing, which is the beater room. All beater rooms where straw board or paper is manufactured are equipped with beaters of various makes and the beating engine itself is equipped with washing apparatus of therotary or circular type and a method was practised for somey time of washing cooked straw with a solution of lime used for softening purposes. However, there is now in use a new method of softening straw in a rotary for the manufacture of strawboard or paper by using lime sulphur, it being a patented process which has been developed by the paper mill laboratories, but lime sulphur, acts very differently from lime 4water and the washing arrangement which operated entirely satisfactory for the purpose intended with the solution used is not adequate where lime sulphur is used in the manufacture of strawboard or paper, for the reason that if the stock was not properly washed, in passing to the next step in its manufacture, which is the paper machine, this lime sulphur would rise to the surface of the sheet on the dryers and form a crust or case hardening which prevented the qiuck movement of moisture from the sheet and with a given number of dryers to produce a given amount of tonnage it was very soon discovered that the new chemical would reduce production to a point that would make the operation of the entire mill a losing venture.

The object of the invention isto overcome the diculty that heretofore existed with the use of lime sulphur in the manufacture of strawboard or paper.

l is a vertical sectional view the rotary showing the connections to the steam pipe and pump in full lines. Fig. 2 is a detail sectional view of the coupling for the steam and water pipe. Fig. 3 is a vertical view on the lines 3-3 of Fig. 1.

Like letters of reference indicate like parts throughout the different views.

The drum is indicated by l. rThe drum has manholes 2 and 3 and the cooked straw is inserted through these manholes. llt is through -to be understood that in the operation of these machines the rotaries usually are capable of holding 7% tons of straw and this straw must be inserted at frequent intervals until the capacity ofthe rotary is reached. It is usual to insert about one-third of the amount at the beginning of the operation and after the rotary has been operated for some period of time additional straw is inserted and this continues until the capacity of the rotary is reached, but toward the end of the normal operation of this rotary the straw is compacted suflicient-ly so that it will iill only part of the rotary and consequently vduring the rotary movement this compacted straw will be thrown from one part of thel rotary to the opposite part thereof. ln order to adapt the rotary for the new method employed therein, I found it desirable to use a perforated plate 4 which is secured to the rotar nearone end thereof as shown in Fig. l. his plate may be inserted in section through the manhole or it may be built in the rotary when same is constructed, but it is preferably shown riveted to the sides of the rotar and is so placed that there is aY space 5 ormed between the plate and the end of the rotary. This plate is shown at the right hand side of Fig. l. The perforations 6 are of such number and arranged in suoli a way that they will permit of the escape of the water hereinafter referred to and they co-operate with the movement of the compacted straw to permit the escape of water. rlhe rotary l is supported on bearings 7 and 8 in any ausual and ordinary way and same is rotated in the. regular way which is a series of gearing, one of which is indicated by 9, which reduces the rotary to a speed for practical operation of same.

l r.lhere is also shown a pipe connection for the steam and water at the left hand side of Fig. 1. This pipe ,is marked l() and is secured to the inside of the rotary by clips 1l and the lower end of the pipe extends to a point near one of the manholes, it being apparent that themanholes are od set one from the other. This pipe terminates as shown in Fig. 2 in a socket 12 formed on the end of pipe 13 which is a stationary pipe extending from the water and steam connection. The pipe l() rotates with the' rotary and there is formed an ordinary loose connection between the pipe 12 and the pipe 10 as shown clearly in Fig. 2 which enables the pipe 10 to rotate independently of the pipe 13. There is also shown means such as glands 14 for protecting the device from the escape of steam,

The water pump is indicated by l and the 5 pipe 16 extends from the pump to the pipe 13. 'lhere is also shown a pipe V17 which is connected with any ordinary steam device.

In the beginning of the operation the water connections are shut off by Valves 18 ll and 19, the valve 19 being located on the outlet pipe 20 which also extends within the rotary by means of the connecting pipe 2l. Pipe 21 is securely fastened to the outer section or half of steam joint or coupling 22, If) whichY is connected on outside end of journal and remains in a fixed position inside o rotary. Coupling or steam joint 22 is similar to the 'coupling or steam joint shown in Figure 2 which enables pipe 21 to remain stationary and is for the same purpose as pipe 20, both `for the purpose of discharge and as appears clearly in Fig. 1, the lower end of the pipe 21 terminates near the lower edge of plate 4 and this is arranged so as to 25 insure the water and lime sulphur siphoning out of the rotary at the end of vthe operation as will be more fully explained hereafter.

The normal operation of this apparatus and method is to insert with the straw or 3" through the manholeafter the straw has been first inserted, a suficient amount of lime sulphur to cause the straw when cooked to be sufficiently softened, after a period of 8 or 10 hours, to make it suitable for forming 35 straw board or paper. This lime sulphur remains in the rotary until the straw ltself is about tobe removed; and the steam connections are kept open so that during the period of 8 hours the straw iskept within 4G the rotary under about 40 pounds steam pressure and this with the lime sulphur'causes the straw, to be sufficiently softened for its intended purpose. After this has been accom- "plished the valve 23 shown in thesteam pipe 17', is operated to shut off the steam connection and the valves 18 and 19 vlare then opened and the pum or other mechanism started to pump water into the rotary. Under the old method or the general practiceimmediately after the :8 or `10 hour cooking period .the steam is shut olf the rotary,

the rotary stopped and a pipe line is connected with a blow oil" valve whichis set generally about 2 feet in front or back of the head or manhole; after this blowvo line is arranged the operator opens. blow olf valve and in this method the pressure is reduced to where the manhead can be taken out and the contents of rotary dumped into what is known as"a stock room, but with the new apparatus the time lost during the blow off period which is about 45 minutes is now used as washing time or for washing purposes.

if ll have described in the above paragraph various valves and pipe lines for the handling of steam or water and the relieving of the water during the washing process and this washing process is continued until the consistency of the chemical, which slows the stock through the mill, is reduced to where the present washing arrangement in the beater room is sufiicient to clear the stock so that the production on machine is not interfered with.

After carrying on this washing arrangement in the rotary for a suificientperiod of time the pump is shut down and Valve 18 is closed, valve 19 is left op'en until the liquor or solution is siphoned or until the vacuum is broken on the end of pipe 21. The rotary is then stopped, manhead taken out, and the discharging of contents of rotary is carried on in the usual manner. This washing operation in rotary isnot a loss of time, it has been going on during the period which otherwise would have been consumed in blowing down pressure which would permit the operator to 'get out manhead and get the rotary up to the present point above described and this produces a stock which is now in shape to be handled without loss of production in other departments of a mill.

It is usual in straw board or paper plants to operate the rotar room during the day time, the balance of the mill is, a 24' hour operation. The night period of rotary room operation is the time consumed in cooking and dumping, all mills having rotary capacity enough to carry on the opera-tion as stated above.

It is further to be understood that the water is forced into the rotary immediately v after the cooking operation is completed and it lis therefore im ortant to use a4 pump or other means of s 'cient size and power such that the water will be forced into the rotary against40 pounds steam pressure or, thereabout.

Having described the invention, I claim as follows: l

l. The method of treating straw for straw vboards or papers by first rotatin same in a in making straw board or paper by rotating l same in a closed vessel for a predetermined period of time having therein a lime sulphur solution with steam` applied to said closed vessel under pressure and after a predetermined'period of rotation shutting oif-the application of steam and then applying water v tinuing will be made ressure of the entrapped steam `through sai vessel into a restricted outlet for said vessel whereby the pressure of the steam will be reduced while the solution is being likewise diluted and partially removed from said vessel. 3.. The method of softening straw for straw board or paper purposes by first rotating same in t e presence of steam under pressure and a. lime sulphur solution for a redetermined period of continuing the rotation of same with a ow against the` of water passing through said straw, simul taneously reducing the pressure of the steam and diluting the solution whereby vthe straw suitable for more profitable operation.

4. The method of treating straw for straw board or paper by first rotating same in a closed vessel with a chemical solution suitable for softening the straw in the resenee of'steam under pressure and therea er conthe rotation of said rotary with a restricted outlet in said vessel and applying time and thereafter water against the pressure of thesteam held in said vessel whereby the water will ow through same reducing the pressure Iof the steam and simultaneously removing from the vessel a portion of the said solution.

5. The method of treating straw by rotating same in a closed vessel with a c emical so ution for softening the straw in the presence of steam maintained for aesubstantial period of time and thereafter subjecting same to a washing process by applying water gains't the pressure of the steam for a peri of time amountin to only a fraction of the irst mentione period of ,time while continuin the rotation of saidrotary with a restricte outlet in saidvessel whereby the pressureA of the steam'will gradually be reduced yand a portion of the solution be simultaneously removed from said vessel by a siphoning action. 4

In testimony whereof, I have hereunto set my hand this eighth day of May, 1926.

DE WITT C. AMERINE. 

